Portable desk



FIG. 1 is a plan view of a portable desk showing my new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a right side elevational view thereof, the left side elevational view being a mirror image;

FIG. 4 is a bottom view thereof;

FIG. 5 is a rear elevational view thereof; and

FIG. 6 is a cross-sectional view thereof taken along lines 6--6 in FIG. 1 and drawn to a larger scale. 

The ornamental design for a portable desk, substantially as shown and described. 